UDPPeer(xEnable:= xEnable, uiPort:= uiPort, ipAddr := IPAddress ,hPeer=> Peer);

PROGRAM PLC_PRG
VAR
  eState: INT:= 0;
 
  IPAddress : NBS.IP_ADDR; (* IP Address *)
  uiPort : UINT; (* Port No. *)
  sReceived : STRING; (* Holds the received message *)
  ctRecAnswers : CL2.CAA.COUNT; (* No. of received messages *)
 
  UDPPeer : NBS.UDP_Peer; (* FB UDP Peer *)
  XUDPPeer : NBS.UDP_Peer; (* FB UDP Peer *)
  UDPSend : NBS.UDP_Send; (* FB UDP Send *)
  UDPReceive : NBS.UDP_Receive; (* FB UDP Receive *)
 
  Peer : CL2.CAA.HANDLE; (* Handle to the peer connection *)
 
  xEnable : BOOL;
 
  udpData :STRING;
END_VAR
UDPPeer(xEnable:= xEnable, uiPort:= uiPort, ipAddr := IPAddress ,hPeer=> Peer);
CASE eState OF
0: // Init
IPAddress.sAddr:= '239.12.255.254';                // IP Adress where Codesys application is running
uiPort:= 9522;
xEnable:= TRUE;
eSTATE := 10;
10: // Start listening
IF UDPPeer.xActive THEN
  UDPReceive(xEnable:= TRUE, hPeer:= Peer, szSize:= SIZEOF(sReceived), pData:= ADR(sReceived));
  IF UDPReceive.xReady THEN
    udpData := sReceived; // Data from UDP-stream
    ctRecAnswers := ctRecAnswers + 1; // Number of UDP calls
  ELSIF UDPReceive.xError THEN
    eState:= 20;
  END_IF
ELSE
  eState:= 20;
END_IF
20:
// Error
END_CASE

VAR_INPUT
   xEnable:BOOL;               //Connect to other system (only at first block)
   xSendData:BOOL;               //Allow to send Data 
   xReadData:BOOL;               //Allow to read Data
   tSendIntervall:TIME:=T#100MS;    // send intervall: standard is 200ms interval
   udiStartAddr:UDINT;            // Start address of Sync-List to Slave
   udiEndAddr:UDINT;            // End address of Sync-List to Slave
   sOtherIPAdr:STRING;            //IP-address of other System
   sOwnIPAdr:STRING;            //IP-address of own System
   uiport: UINT;                //port number for comunication
END_VAR
VAR_OUTPUT
   xConnectionDone:BOOL;         // Output = TRUE if Connection is established
   xConnectionBusy:BOOL;         // Output = TRUE if there it try to establish the Connection
   xConnectionError:BOOL;         // Output = TRUE if there is a connection error
   xSendDone:BOOL;               // Output = TRUE if data were send
   xSendBusy:BOOL;               // Output = TRUE if data exchange is in progress
   xSendError:BOOL;            // Output = TRUE if data exchange failed
   eSendError:NBS.ERROR;         // Defined Errors of Struct in NBS.ERROR
   xReceiveBusy:BOOL;            // Receive currently active
   xReceiveError:BOOL;            // Receive error
   eReceiveError:NBS.ERROR;      // Defined Errors of Struct in NBS.ERROR
   xReceiveReady:BOOL;            // When data was read successfully
END_VAR
VAR
   myUDP_Peer:NBS.UDP_Peer;       //to connect to other System
   myUDP_Receive:NBS.UDP_Receive;    // to receive data from other System
   myUDP_Send:NBS.UDP_Send;       //to send data to other System
   other_ip_Addr: NBS.IP_ADDR;    // to set IP-Address of other System
   own_ip_Addr: NBS.IP_ADDR;       // to set IP-Address of own System
   myBlink:BLINK;                //to define send-interval
   tTimeIntervall:TIME;         //Time interval to send data
   peerHandle: NBS.CAA.HANDLE;    // to identify other System
   xEnableReceive:BOOL   ;         // Enable to receive Data
END_VAR

(*--------------------*)
(*Data synchronisation*)
(*--------------------*)
//Get IP from other system
other_ip_Addr.sAddr:=sOtherIPAdr;
own_ip_Addr.sAddr:=sOwnIPAdr;
//Connect via UDP
myUDP_Peer(xEnable:=xEnable, 
         ipAddr:=own_ip_Addr, 
         uiPort:=uiport, 
         xDone=>xConnectionDone, 
         xBusy=>xConnectionBusy, 
         xError=>xConnectionError);
         
//save peerHandle
peerHandle:=myUDP_Peer.hPeer;
IF xEnable AND xConnectionBusy AND xSendData THEN
   //UDP send
   //Send interval (Input have to be devided because Low-Time +High-Time = intervall 
   tTimeIntervall:=tSendIntervall/2;
   myBLink(Enable:=TRUE, TimeLow:=tTimeIntervall, TimeHigh:=tTimeIntervall);
   myUDP_Send(xExecute:=myBLink.OUT, 
            udiTimeOut:=100000, 
            hPeer:=peerHandle, 
            ipAddr:=other_ip_Addr, 
            uiPort:=uiport, 
            szSize:=(udiEndAddr-udiStartAddr(*+SIZEOF(udiEnd)*)), //+SIZEOF ist auskommentiert, da sonst mehr mitgeschickt wird als gewollt => so wird lediglich das "End-Bool" nicht mitgeschickt.
            pData:= udiStartAddr, 
            xDone=>xSendDone, 
            xBusy=>xSendBusy, 
            xError=>xSendError, 
            eError=>eSendError);
END_IF   
   
IF xEnable AND xConnectionBusy AND xReadData THEN   
   //UDP receive
   //Bei fehler neu starten
   IF xReceiveError THEN
      xEnableReceive:=FALSE;
   ELSE
      xEnableReceive:=TRUE;
   END_IF
   
   myUDP_Receive(xEnable:=xEnableReceive, 
            hPeer:=peerHandle, 
            szSize:=(udiEndAddr-udiStartAddr(*+SIZEOF(udiEnd)*)),
            pData:=udiStartAddr, 
            xBusy=> xReceiveBusy, 
            xError => xReceiveError, 
            eError=>eReceiveError, 
            xReady=>xReceiveReady);
END_IF